Bicycles have existed for many years throughout serving as transportation and sporting means. Over the great time span since their inception, the technology has evolved with numerous designs and advancements predominantly geared toward addressing rider comfort. With the initial designs from many years ago comprising a single speed power transmission mechanism often requiring the rider to either exert undue effort on the pedals or have to alternate the pedals at an uncomfortably high rate to achieve desired riding speed, a need was recognized for multiple powertrain ratios to facilitate acceptable operator pedaling rates and efforts. A variety of designs consequently evolved where additional power transmission drive sprockets of various number of teeth but equal pitch to the drive chain were added in the axial directions of the pedals mechanism as well as power transmission rear wheel hub to facilitate a combination of front and rear power transmission ratios resulting in optimal settings based on desired vehicle speeds, road conditions, operator biometrics and preference. This innovation was facilitated by the de-facto standard four bar linkage mechanism based derailleur assembly used to this very day to alternate drive sprockets through properly positioning the drive chain thereto as well as compensate for resultant varying chain lengths through an integral spring loaded chain tensioning mechanism. This capability was facilitated by two cable tensioning apparatuses, one for rear sprockets and another for the fronts. With one end of each cable apparatus connected to the derailleur chain positioning mechanism and the other end to an operator actuation mechanism typically comprising a lever assembly, this apparatus granted the operator the ability to alternate the chain position in the axial position for proper alignment and thereby engagement of selected rear and front drive sprockets in order to achieve optimal power transmission ratio settings. Advancements in the actuation mechanism included indexing capability of the operator lever assembly so that the actuation of the gearing mechanism takes place in an indexing fashion consistently properly aligning the chain with desired sprocket thereof rather than one continuous motion requiring the operator to guess the proper chain position often leading to positioning errors, inefficiency and premature chain wear.
On a most fundamental level, the de-facto chain derailleur design used to this very day requires chain movement in the forward direction in order to operate. Circumstances often arise where a bicycle shift is needed but chain motion is not available in situations such as during braking or coasting where the rider has ceased to operate the pedals, the derailleur is inevitably left in the wrong speed setting, or in other words with the derailleur engaged with the wrong sprocket. In the event where the rider has stopped, a restart in a high drive sprocket is often required leading to undue effort from the rider and poor ergonomics where the rider upon initiating motion, however difficult, expends a great deal of attention and effort alternating the shifter into a more ideal setting. Another type occurrence albeit less serious is when the rider is coasting downhill and has also ceased to operate the bicycle pedals, depending on the road condition, upon need to continue to pedal, the bicycle speed is invariantly in the wrong setting.
The inventor hereby discloses a novel improvement to the standard sprockets derailleurs based bicycle drivetrain by means of a chain driver apparatus providing on demand capability to the rider for energizing the bicycle drive chain in the forward direction through simple actuation of an electrical pushbutton enabling operation of the bicycle derailleurs to achieve desired setting, whether the bicycle is in motion or is in a complete stop, henceforth providing a more comfortable and ergonomic experience for the rider.